Delivery of biologically active agents

ABSTRACT

A method of delivering a biologically active agent to the cervix, the method comprising using a needleless injector. Typically, the biologically active agent is a cervical ripening agent. The needleless injector may be a powder injector or a liquid injector.

The present invention relates to the delivery of biologically activeagents to the female cervix and, in particular, it relates to thedelivery of cervical ripening agents.

The cervix acts as a barrier to the ingress of infection as well as arigid barrier at the neck of the womb. This organ has relatively littlemuscle with the majority of the strength of the organ derived fromcollagen. In a normal, easy delivery, the cervix has to soften andstretch (eface) to allow the baby's head to pass through, if this can beachieved with little uterine contractility then subsequent contractionscan deliver the baby with minimal trauma for mother and child.

Biologically active agents such as prostaglandins and chemokines aredelivered to the cervix or vaginal fomix for various purposes. Inparticular, agents are delivered to aid cervical ripening for a numberof reasons including (a) the induction of labour, (b) to soften anunfavourable cervix during labour, (c) to assist medical termination ofpregnancy, (d) to assist uterine surgery and (e) to accelerate normalparition and to reduce the accompanying risks and discomforts. U.S. Pat.No. 5,624,670 to Kelly et al describes the use of interleukin-8 (IL-8)for inducing cervical ripening, and U.S. Pat. No. 5,908,829 to Kellydescribes the use of monocyte chemotactic peptide-1 (MCP-1) for inducingripening of the cervix.

Vasodilators or their precursors (such as the nitric oxide donornitroglycerine) are also delivered to the cervix.

At present, biological agents are delivered to the cervix or vaginalfornix using gels, creams, pessaries. A relatively large amount of drugis currently needed since diffusion through the epithelial layers of thecervix is relatively slow. The gel can also get displaced. The mostcommon current method of cervical ripening is to use prostaglandin E₂.This is used as a vaginal gel or tablet or as a gel placed in thecervix. Typically, gel is placed in the vaginal fornix. Theprostaglandin has to diffuse through the epithelium of the cervix andact on the blood vessels to increase permeability. In additionprostaglandin may act on fibroblasts to release interleukin-8 (IL-8)within the cervix. The combination of IL-8 and PGE is very powerful inattracting neutrophils (Colditz (1990) Immunol. Cell Biol. 68, 397-403)and neutrophils are a source of collagenase.

There are several disadvantages to the current approaches. Firstly, inorder that sufficient amounts of the biologically active agent aredelivered to the site of action, relatively high concentrations of theagent need to be included in the formulation administered. Secondly,prostaglandin gels used to ripen the cervix by administration to thevaginal fornix can stimulate the myometrium to contract excessively and,in extreme circumstances, an uterine rupture can occur (Maymon et al(1991) Am. J. Obstet, Gynecol. 165, 368-370). Thirdly, withprostaglandin gel the rate of diffusion into the cervix is limited andvariable. Fourthly, for certain of the biologically active agentsdelivered to the cervix or vaginal fornix, diffusion is relatively slowdue to the increased molecular size and hydrophilic nature of thecompound. This is particularly true for peptide agents.

During its ripening, the cervix is thought to soften from the internalos. That is likely because of the possible fetal contribution to thetiming of birth. Thus, the initial softening might involve agents (suchas PGE₂ and or chemokines) diffusing outward from the fetal membranes(amnion and chorion) to the point of contact with the cervix, theinternal os. Attempts to deliver chemokines has identified a problemwith the diffusion of the active agent, particularly when that agent isa peptide and accordingly may not be lipophilic.

In addition, we believe that delivery to the cervix of any ripeningagent should be diffuse rather than punctate and thus conventionalinjection using a needle and syringe is not ideal.

There remains the need to improve on delivery methods to the cervix and,as described in more detail below, the inventors believe thatalternatives lo which use needleless injectors may lead to benefits overthe existing methods.

Needleless injectors are well known in the art and have been used todeliver agents principally to the skin of individuals, for example invaccinations. As far as the inventors are aware, despite needlelessinjectors having been available for very many years, no-one hassuggested that they would be useful in delivering agents to the cervix,and no-one has realised the potential benefits in terms of thepossibility of using lower concentrations of biologically-active agents,particularly cervical-ripening agents such as prostaglandins, andbenefits in terms of potentially simplifying the formulation of theactive agents for delivery. In particular, compared to other deliverymethods, no gel matrix (such as a methyl cellulose or modified starchgel) is required.

Commercially available needleless injectors fall into two maincategories: those which use powder formulations of the biologicallyactive agent, and those that use the agent in a solution formulation.These will be referred to as “powder” injectors and “liquid” injectors.Generally, both types of injector use compressed air, or gas, or sometype of mechanical configuration to “inject” the active agent into thepatient.

Powderject (Oxford, UK) manufactures commercially powder injectors.Typically, powder injectors make use of dry powder formulations and fineparticles of the drug to be delivered are projected at high velocitywithin a brief burst of, typically, helium gas. Transdermal applicationhas been described and, typically, the dose is delivered over a skinarea of up to 2 cm².

WO 94/24263 (Oxford Biosciences Limited) describes a needleless syringewhich uses supersonic gas flow for particle delivery. The needlelesssyringe has a membrane which is ruptured by gas pressure to generate asupersonic gas flow in which particles containing a therapeutic agentare injected. WO 96/12513 (Oxford Biosciences Limited) describes asimilar system except that a soft-walled capsule, such as one with agelatine wall, is used to hold the therapeutic agent in the syringe. WO96/20022 (Oxford Biosciences Limited) again describes a similar deviceexcept that it has a diaphragm which snaps from inverted to evertedpositions to catapult particles outwardly.

WO 96/25190 (Oxford Biosciences Limited) describes a needleless powderinjector with a bend.

WO 97/34652 (Powderject Research Limited) relates to a shroud whichsurrounds the nozzle of the syringe and reduces the noise.

WO 98/13470 (Powderject Vaccines, Inc) relates to a rotational flowelement which modifies gas flow through the device.

WO 99/01168 and WO 99/01169 (Powderject Research Limited) relate to aprefilled capsule for use with a powder injector and a modified gasrelease mechanism, respectively.

WO 00/54827 (Powderject Research Limited) relates to a diaphragm for usewith a needleless injector wherein the diaphragm provides for enhancedparticle retention.

WO 00/62846 (Powderject Research Limited) relates to a needleless powderinjector device that does not require particles to be between burstablemembranes.

Certain other patent applications relate to the manufacture of particlecompositions (WO 97/48485 and WO 00/53160; Powderject Research Limited);and cartridges for use in a needleless powder injector (WO 98/21364;Powderject Vaccines, Inc and U.S. Pat. No. 5,780,100 to McCabe andHeinzen).

Weston Medical (Peterborough, UK) manufactures commercially liquidinjectors.

WO 93/03799 (Weston) and WO 95/03844 (Weston Medical) describe a liquidinjector system which is used to deliver vaccines by penetration of theepidermis for intradermal delivery. WO 96/28202 (Weston Medical) and WO97/37705 (Weston Medical) describe a spring-powered dispensing devicewhich can be in the form of a needleless injector. EP 0 520 571 A(Glaxo) describes an atomising nozzle for use with a liquid injector. WO96/15821 (Weston Medical) describes a glass container for use inneedleless injectors, and WO 97/22375 (Weston Medical) and WO 97/36785(Weston Medical) describe a needleless injector drug capsule and fillingmethod.

WO 96/19252 (Weston Medical) describes a filling device for a needlelessinjector. WO 00/10630 (Weston Medical) describes an actuator for a gaspowered needleless injector. WO 00/15281 (Weston Medical) describes aneedleless injector cartridge.

A first aspect of the invention provides a method of delivering abiologically active agent to the cervix, the method comprising using aneedleless injector.

The delivery may be directly to the cervix or may be via the vaginalfornix, which is a fold in the vagina where the cervix is located. Thus,the end of the needleless injector may occupy the vaginal fornix anddelivery may be at or through the vaginal fornix into the cervix.

Typically, injections will aim at the cervix but may be aimed fromdifferent angles.

Preferably, the site of injection is “off-centre” into the cervicallumen or into any part of the externally presenting area of the cervix.

The needleless injector may be any suitable man-made needleless injectorand, conveniently, may be a liquid injector or a powder injector asdescribed above. Thus, suitable needleless liquid injectors includethose manufactured by Weston Medical Limited, Peterborough, UK and thosedescribed in WO 93/03779, WO 95/03844, WO 96/28202, WO 97/37705 and WO00/10630, all of which are incorporated herein by reference.

Suitable needleless powder injectors include those manufactured byPowderject Research Limited, Oxford, UK and those described in WO94/24263, WO 96/12513, WO 96/20022, WO 96/25190, WO 97/34652, WO98/13470, WO 99/01168, WO 99/01169, WO 00/54827 and WO 00/62846, all ofwhich are incorporated herein by reference.

The biologically active agent may be loaded into the injector by meansknown in the art.

It may be useful if the needleless injector has a “bent” configurationsuch that delivery of the biologically active agent is to the cervixrather than to the walls of the vagina or to the entrance of the cervix.Thus, the needleless injector may be adapted for this purpose, and thegeometry of the device arranged such that there is easy passage throughthe vagina but that the exit from the injector (ie outlet orifice) isangled such that the biologically active agent is delivered efficientlyto the desired site on the cervix. The type of injectors described in WO96/25190 may be particularly suitable; however, rather than the internalangle of approximately 90° shown in FIGS. 1 to 4 of WO 96/25190, it maybe more appropriate if the internal angle of the head to the shaft isbetween 20° to 90°; preferably between 35° and 85°, for example 65°.

The arrangement of the head containing the outlet orifice shown in FIG.16B of WO 00/54827 may also be particularly suited for use in thepresent invention. Similarly, the arrangement shown in FIG. 5 of WO00/62846, where the exit plane is not perpendicular to the longitudinalaxis of the nozzle, but angled, may be particularly suited for use withthe invention.

The biologically active agent may be any agent for delivery to thecervix which has a useful effect. For example, the agent may be anyagent which has a therapeutic or prophylactic effect, or which is usefulin any medical procedure. Typically, the agent is one which is useful ingynaecology or obstetrics.

Suitable agents include prostaglandins (both natural and synthetic),vasodilators or their precursors (such as the nitric oxide (NO) donor,nitroglycerine), and chemokines or any cytokine that could stimulatemonocyte or granulocyte entry into the cervical tissue such as GM-CSF.

It is particularly preferred if the agent is a cervical ripening agent,such as a prostaglandin (in particular, prostaglandin E₂) orinterleukin-8 (IL-8) or monocyte chemotactic pepfide-1 (MCP-1) orcombinations thereof. MCP-1, IL-8 and variants thereof may be obtainedby chemical synthetic methods or by recombinant DNA means as is wellknown in the art. Prostaglandins, such as PGE₂, are commerciallyavailable, for example from Pharmacia and Upjohn. The use ofprostaglandins in cervical ripening is well known in the art. The use ofIL-8 and MCP-1 in cervical ripening is described in U.S. Pat. Nos.5,624,670 and 5,908,829, respectively, incorporated herein by reference.Variants of MCP-1 or IL-8 which are able to induce cervical ripening mayalso be used.

A “variant” refers to a protein wherein at one or more positions therehave been amino acid insertions, deletions, or substitutions, eitherconservative or non-conservative, provided that such changes result in aprotein whose basic properties, for example cervical ripening-inducingactivity, thermostability, activity in a certain pH-range (pH-stability)have not significantly been changed. “Significantly” in this contextmeans that one skilled in the art would say that the properties of thevariant may still be different but would not be unobvious over the onesof the original protein.

By “conservative substitutions” is intended combinations such as Gly,Ala; Val, Ile, Leu; Asp, Glu; Asn, Gln; Ser, Thr; Lys, Arg; and Phe,Tyr.

Such variants may be made using the methods of protein engineering andsite-directed mutagenesis as described below.

The dose of the agent administered is any suitable dose of the agentwhich provides the desired effect of the agent. Typically, because ofthe precision with which the agent can be administered with theneedleless injector, the dose may be significantly reduced compared tothe dose administered by other, conventional means. The amount may bereduced to 50% or 20% or 10% or 5% or 2% of the amount normally used,depending on the agent administered.

For example, 2 to 100 μg of IL-8 or MCP-1 dissolved in 200 μl of sterilesaline may be used in a liquid injector.

Diffused delivery is achieved using needleless injectors. The agent,once injected, distributes radially and along the length of theinjection path. Such a method of delivery is not obtainable by any othermethod of injection, and, although not being bound by any theory, isbelieved to be particularly beneficial in the context of the presentinvention.

Administration of lower amounts of the agent may reduce the chance ofside effects. For example, side effects of NO donors are headaches andexcessive bleeding. Injection of a low amount directly into the cervixwould both accelerate the effect and reduce the side effects.

Typically, the needleless injector is loaded with the biologicallyactive agent which is to be delivered to the cervix, the injector isinserted into the vagina such that the exit from the injector (ie outletorifice) is in proximity to the cervix, and the injector is actuated soas to deliver the agent to the cervix. Preferably, the exit from theinjector (ie outlet orifice) is not at the rim of the cervix but is atthe side of the cervix.

It will be appreciated that position or type of “head” of the needlelessinjector (ie that contains the outlet orifice) may be adjusted oradapted depending on the particular use. Thus, particular positions ordesigns of head may be more suited to delivery when the cervix ispartially dilated (eg during parturition) or may be more suited todelivery when the cervix is closed or substantially closed.

A description of the anatomy of the vagina, cervix and uterus is givenin FIG. 1 and positions for possible delivery to the cervix areindicated.

The method may be used to deliver biologically active agents to anyfemale mammal, but it is particularly preferred if the method is used todeliver agents to a human female. However, the method may be especiallyuseful for sheep where in vitro fertilization and embryo transferprocedures currently involve laparoscopy which brings up ethical andanimal husbandry considerations, the problem being that the cervix isimpenetrable. It is believed that a diffuse injection of cervicalripening agent would give a very rapid response, allowing a wider use ofin vitro fertilization.

It will be appreciated that for certain agents, in particular peptideand polypeptide agents, it may be appropriate to select the peptide orpolypeptide of the mammal, or a closely related molecule foradministration. Thus, for example, it is preferred to administer humanpeptides or polypeptides to a human female. Of course, the peptide orpolypeptide may be produced synthetically or by recombinant DNA meansbut would still be considered “mammalian” or, as the case may be“human”. Suitable IL-8 molecules and derivatives thereof are describedin U.S. Pat. No. 5,624,670, incorporated herein by reference. SuitableMCP-1 molecules and derivatives thereof are described in U.S. Pat. No.5,908,829, incorporated herein by reference.

It will be appreciated that the invention includes a method of ripeningthe female cervix, the method comprising administering a cervicalripening agent to the cervix using a needleless injector. The method canbe used for the induction of labour at term (ie time of ordinary birth),but it may also be used for the induction of pre-term labour, andinduction of labour in connection with a pathological pregnancy, or inconnection with intrauterine fetal death. It may be used to ripendysfunctional cervices, ie when dilation stops before completion. Themethod may also be used for preliminary cervical ripening prior toinduction of abortion (eg in the first or second trimester abortion),and for induction of cervical ripening of a non-pregnant or pregnantfemale to assist surgical or diagnostic procedure such as D&C. Cervicalripening may also be induced in the female for the purposes of treatmentby in vitro fertilisation.

It is particularly preferred if the cervical ripening agent is any oneor more of IL-8, MCP-1 or a prostaglandin. The prostaglandin typicallyis PGE₂ which is currently used in cervical ripening. It is believedthat by using the methods of the invention, which may be used to moreaccurately deliver the agent to a particular site on the cervix, asmaller amount of agent may be used compared to the use of gels, creams,pessaries and the like. At least in the case of PGE₂ this has thepotential benefit of reducing the risk of undesirable contraction of themyometrium. The amount of PGE₂ may be reduced to 10% or 5% or 2% of theamount normally used when in a gel. For example, 2 to 100 μg of PGE₂dissolved in 200 μl of sterile saline may be used.

The cervical ripening agent may be a combination of agents. It isparticularly preferred if the cervical ripening agent is a complexcomprising a proteinaceous agent which is chemotactic for monocytesand/or neutrophils and a prostaglandin.

By “proteinaceous agent which is chemotactic for monocytes and/orneutrophils” we include any protein or polypeptide or oligopeptide orpeptide which is able to encourage monocytes and/or neutrophils into atissue where the agent is present.

Typically, the agent is a proteinaceous cervical ripening agent.

By “proteinaceous cervical ripening agent” we include any protein orpolypeptide or oligopeptide or peptide which has the ability to induceripening of the cervix when suitably administered to the female. Thus,the proteinaceous cervical ripening agent is one which contains peptidebonds and has amino acid side chain residues.

Preferably, the proteinaceous agent which is chemotactic for monocytesand/or neutrophils is one with a pI value of 7.5 or above, preferably 8or above and more preferably 8.5 or above. Typically, >5% of the aminoacid residues are lysines.

The prostaglandin may be any suitable prostaglandin. It is preferredthat the prostaglandin is one which is able to induce cervical ripeningwhen suitably administered to the female. It is preferred that theprostaglandin is PGE₂ or a synthetic analogue thereof with a free acid.Synthetic analogues include these modified at position 15 by theaddition of a methyl group.

It is particularly preferred if the prostaglandin is one which has anacidic group such as a carboxylate group. Preferably, the acidic groupis one which, under low pH conditions, gives a free acid.

It is preferred that the prostaglandin is prostaglandin E₂ (PGE₂).

Particularly preferred proteinaceous cervical ripening agents includemonocyte chemotactic peptide-1 (MCP-1) or interleukin-8 (IL-8) orvariants thereof which retain the ability to induce cervical ripening.

These complexes are described in our co-pending PCT Patent Applicationwhich claims priority from UK Patent Application No 0103354.7.

A second aspect of the invention provides a system for delivering abiologically active agent to the cervix comprising an agent which isbiologically active on the cervix and a needleless injector.

The needleless injector may be any needleless injector suitable fordelivering the agent to the cervix. Such needleless injectors aredescribed above and preferred injectors in the above mentioned methodsof the invention are also preferred in this aspect of the invention.

The biologically active agent is an agent which is active on the cervix.Suitably, the agents are ones which are delivered to the cervix fortherapeutic or prophylactic or other medical use. Typically, they areagents which are not ones which are administered to the skin. Suitablesuch agents include PGEs, IL-8 and MCP-1 as described above.

The agents preferably include cervical ripening agents as describedabove.

The system may be considered to be a kit of parts comprising variouscomponents. Thus, the kit of parts may comprise a needleless injectorand, separately, the biologically active agent. In that case, the agentmay be loaded into a suitable reservoir in the needleless injector.Alternatively, the kit of parts may comprise a needleless injector and avial (by which we include capsule or cartridge or the like) whichcontains the agent wherein the vial is one which can be loaded into theinjector. Additionally, in the case of powder injectors, the kit maycontain the therapeutic agent in a suitable, powdered form. Similarly,in the case of liquid injectors, the kit may contain the therapeuticagent in a suitable solution.

It will be appreciated also that the system of this aspect of theinvention may also comprise a needleless injector which is pre-loadedwith the biologically active agent.

Vials (or capsules or cartridges) for use with a needleless injector aredescribed in more detail below.

A third aspect of the invention provides a needleless injector loadedfor injection with an agent which is biologically active on the cervix.The needleless injector may be any suitable needleless injector asdescribed above, and the agent which is biologically active on thecervix may be any agent as described above. The needleless injectorloaded with the agent according to this aspect of the invention may beformed by introducing a vial which contains the agent into the injector.Alternatively, the agent may be introduced into an existing reservoirwithin the needleless injector.

A fourth aspect of the invention provides a vial for insertion into, andcontaining an agent for delivery by, a needleless injector wherein theagent is an agent which is biologically active on the cervix.

The term “vial” may be interchanged with “cartridge”, “capsule” and thelike, unless the context indicates otherwise. In particular, it includesthe burstable membranes described in WO 94/24263 and the soft-walledcapsules described in WO 96/12513.

Certain needleless injectors, for example those described in WO93/03779, WO 95/03844, WO 00/10630, WO 94/24263, WO 96/20022 and WO96/25190 are designed to receive pre-charged vials containing the agentto be “injected”. Thus, the vials of this aspect of the inventioninclude such vials pre-charged with an agent which is biologicallyactive on the cervix, such as those described above and, in particular,cervical ripening agents. Accordingly, the vials are of the correct sizeand shape to fit into the appropriate needleless injector. Also, thevials are made of appropriate material for their purpose. Suitably, thevial contains a unit dosage of the biologically active agent. Suitably,when used in a liquid needleless injector, the vial contains around 200μl (for example, between 50 μl and 500 μl). Typical unit dosages are 2to 100 μg of the agent, such as PGE2 or MCP-1 or IL-8.

Suitable vials for use with certain needleless liquid injectors, andmethods of manufacture and filling the same, are described in WO00/15281, WO 97/36785, WO 97/22375, WO 96/19252, WO 96/15821, WO98/12121 and WO 98/13086, all of which are incorporated herein byreference.

Suitable vials for use with certain needleless powder injectors, andmethods of manufacturing and filling the same, are described in WO00/54827, WO 00/62846, U.S. Pat. No. 5,780,100, WO 98/21364, WO99/01169, WO 96/20022, WO 96/12513 and WO 94/24263.

A fifth aspect of the invention provides a method of preparing aneedleless injector for use in delivering a biologically active agent tothe cervix, the method comprising loading the injector with thebiologically active agent. The biologically active agent may be loadeddirectly into a pre-existing eservoir within the needleless injector orit may be loaded into the injector in a pre-charged vial.

A sixth aspect of the invention provides a pharmaceutical formulationcomprising an agent for delivery to the cervix and a carrier suitablefor use in a needleless injector.

The pharmaceutical formulation is typically sterile and pyrogen free.

For liquid injectors the biologically active agent is typicallydissolved in sterile water or sterile saline. However, it may beadvantageous to include a dispersion agent or an agent which allows foror increases transdermal or transmucosal transfer or penetration such asdimethyl sulphoxide (DMSO) and the like.

For powder injectors the powder to be delivered needs to be of asuitable quality for delivery. Suitable powder (ie particlecompositions) may be made according to the methods described in WO97/48485 and WO 00/53160, incorporated herein by reference. Inparticular, the particles (powder) for use in the present invention havean optimum particle density ranging from about 0.1 to about 25 g/cm³,preferably ranging from about 0.5 to about 3.0 g/cm³, and mostpreferably ranging from about 0.8 to 1.5 g/cm³. The densified particlesare suitably processed to obtain particle sizes ranging from about 0.1to 250 μm, preferably ranging from about 0.1 to 150 μm, and mostpreferably ranging from about 20 to about 60 μm.

Thus, the invention includes particles comprising a cervical ripeningagent such as interleukin-8 or MCP-1 or PGE₂ or combinations thereofwith these physical parameters. These particles may be made using themethods described in WO 97/48485, incorporated herein by reference. Theparticles may be biologically inert particles onto which has been coatedthe biologically active agent. Suitably, the biologically active agentmay be deposited onto the particle by dissolving it in a suitablesolvent and then evaporating the solvent.

A further aspect of the invention provides use of a cervical ripeningagent in the manufacture of a medicament for treating a female in needof a cervical ripening agent wherein the cervical ripening agent is fordelivery using a needleless injector.

Preferably, the cervical ripening agent is any one or more of IL-8,MCP-1 or prostaglandin E₂.

The invention will now be described in more detail by reference to thefollowing Examples and Figures.

FIG. 1: Anatomy of the human vagina, cervix and uterus.

FIG. 2: View of dye track for three separate cervices injected with theWeston needleless injector. Note the small ruler divisions are in mm.All injections were performed from the face of the cervix that wouldnormally be in the vagina.

EXAMPLE 1 Administration of MCP-1 to a Human Female Using a NeedlelessSyringe

The patient is a human female in need of cervical ripening.

200 μl of solution of monocyte chemotactic peptide-1 (MCP-1) of 100μg/ml in sterile saline is loaded into a helium-loaded injection deviceand the end of the device is placed either in the vaginal fornix againstthe cervical mass or against the exposed cervical lumen. The injector isfired at one or two locations.

EXAMPLE 2 Preparation of IL-8 as a Powder for Injection Using aNeedleless Injector

Lyophilized recombinant human interleukin-8 powder is obtained andreprocessed using the method described in WO 97/48485. Particularly,approximately 30 mg of IL-8 was compacted under pressure using a CarverLaboratory Pellet Press (Model 3620, available from Carver, Inc.,Wabash, Ind.). The pressure of compaction was 15,000 lbs/in², which wasapplied for approximately 45 seconds. A pellet was obtained which wasground using mortar and pestle until visually broken up. The resultingreduced pellet was then sieved using a 53 μm sieve (Endecott, London).Particles having a size greater 53 μm were selected and appropriatedosages thereof were measured into drug cassettes for delivery from aneedleless syringe.

EXAMPLE 3 Use of the Weston Needleless Injector to Evaluate Penetrationof the Cervix

A Weston needleless injector was loaded with 0.2 ml of dye (1 mg/ml ofmethylene blue {Sigma} in phosphate buffered saline). Whole human cervixwas obtained at hysterectomy from non-pregnant women of reproductiveage. The cervix was tested within 30 minutes of removal from thepatient. The needleless injector device was held against the ectocervixregion. Increased pressure on the needleless injector activated thedevice. Two injections were performed for each specimen.

The cervix was dissected along the track of the injection (FIG. 2) andthe length of the dye track was measured. In four experiments the lengthof the track was a mean of 6.1 mm (standard error of the mean=1.9 mm).The mean lateral spread (any signs of the blue dye) was 8.8 mm.

Liquid needleless injectors (eg Weston) penetrate skin but the liquidstream rebounds when it hits muscle. The cervix has relatively littlesmooth muscle (but gets its strength from collagen) and therefore theextent to which the liquid stream would penetrate was unknown untilthese experiments. As far as we can see there is relatively littletissue damage at the site of injection. The lateral spread of theinjected dye is very difficult to see in the black/white photographs butcan be seen in the colour ones from which the black and whitephotographs are derived.

The use of the needleless injector in testing the penetration and spreadof a marker dye shows that the distribution of cervical ripening productwould be ideal for a rapid ripening of the cervix. The relatively widespread of the injected material suggests that the ripening agent wouldget ready access to the vasculature of the cervix. The rapiddistribution will reduce the time for any agent to start the ripeningprocess. Thus the use of such a device together with an effectivecervical softening agent will provide the obstetrician with a usefultool to control the cervical ripening process.

1. A method of delivering a biologically active agent to the cervix, themethod comprising using a needleless injector.
 2. A method according toclaim 1 wherein the needleless injector is a liquid injector.
 3. Amethod according to claim 1 wherein the needless injector is a powderinjector.
 4. A method according to claim 1 wherein the biologicallyactive agent is a cervical ripening agent.
 5. A method according toclaim 4 wherein the cervical ripening agent is any one or more of aprostaglandin, MCP-1 and IL-8.
 6. A method according to claim 1 whereinthe biologically active agent is a vasodilator or precursor thereof, achemokine or a cytokine which stimulates monocyte or granulocyte entryinto cervical tissue.
 7. A method of ripening the female cervix, themethod comprising administering a cervical ripening agent to the cervixusing a needleless injector.
 8. A system for delivering a biologicallyactive agent to the cervix comprising an agent which is biologicallyactive on the cervix and a needleless injector.
 9. A system according toclaim 8 wherein the biologically active agent is a cervical ripeningagent.
 10. A system according to claim 8 wherein the needleless injectoris a liquid injector.
 11. A system according to claim 8 wherein theneedleless injector is a powder injector.
 12. A needleless injectorloaded for injection with an agent which is biologically active on thecervix.
 13. A needleless injector according to claim 12 wherein thebiologically active agent is a cervical ripening agent.
 14. A needlelessinjector according to claim 12 which is a liquid injector.
 15. Aneedleless injector according to claim 12 which is a powder injector.16. A vial for insertion into, and containing an agent for delivery by,a needleless injector wherein the agent is an agent which isbiologically active on the cervix.
 17. A vial according to claim 16wherein the agent is a cervical ripening agent.
 18. A method ofpreparing a needleless injector for use in delivering a biologicallyactive agent to the cervix, the method comprising loading the injectorwith the biologically active agent.
 19. A method according to claim 18wherein the agent is loaded in a vial disposed for insertion into theneedleless injector.
 20. A pharmaceutical formulation comprising anagent for delivery to the cervix and a carrier suitable for use in aneedleless injector.
 21. A pharmaceutical formulation according to claim20 wherein the formulation contains particles of a density between about0.1 and about 25 g/cm³ and of a size between 0.1 and 250 μm whichparticles comprise the said agent.
 22. A pharmaceutical formulationaccording to claim 20 comprising an agent which permeabilises a mucosalsurface, such as dimethylsulphoxide.
 23. Use of a cervical ripeningagent in the manufacture of a medicament for treating a female in needof a cervical ripening agent wherein the cervical ripening agent is fordelivery using a needleless injector. 24-26. (canceled).